# A Diagnostic Challenge: Post‐Transfusion Purpura Unmasked After Multiple Transfusions

## TL;DR

A rare case of post-transfusion purpura is described in a patient with a complex medical history, emphasizing the need for early diagnosis and treatment.

## Contribution

The case highlights the diagnostic challenges of PTP in patients with comorbid conditions and the importance of prompt IVIG therapy.

## Key findings

- PTP was diagnosed after multiple transfusions in a patient with anti-phospholipid antibody syndrome and recent heparin exposure.
- IVIG was ineffective, but plasmapheresis significantly improved platelet counts.
- HPA-1a and HPA-5b antibodies confirmed the diagnosis of PTP.

## Abstract

Post‐transfusion purpura (PTP) is a rare immune‐mediated post‐transfusion reaction resulting in severe thrombocytopenia. This case presents a 52‐year‐old female with profound thrombocytopenia following multiple transfusions. PTP was not initially suspected due to her history of comorbid anti‐phospholipid antibody syndrome (APS), chemotherapy treatments, and recent heparin exposure. Her thrombocytopenia was refractory to intravenous immunoglobulin (IVIG), and she was started on plasmapheresis (PLEX) with significant improvement in platelet counts. Positive human platelet antigen (HPA)‐1a and HPA‐5b antibodies later confirmed a diagnosis of PTP. This case highlights the importance of early recognition of PTP, and treatment should not be delayed while awaiting confirmatory antibody testing.

Post‐transfusion purpura must be considered when severe thrombocytopenia develops 5–10 days post‐transfusion, and therapy with intravenous immunoglobulin should be promptly initiated even before confirmatory HPA testing is available.

Post‐transfusion purpura must be considered when severe thrombocytopenia develops 5–10 days post‐transfusion, and therapy with intravenous immunoglobulin should be promptly initiated even before confirmatory HPA testing is available.